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FAQs-WA Electrical Distribution and Connection Requirements
Q: Do you require installing a Service Protection Device (SPD) in all consumer installations?
Yes. Except for sole-use substations, where the transformer circuit breaker may not be duplicated,
the SPD does not replace the main switch. An SPD and a main switch must be provided on direct
connected metering installations.
SPD to be installed in the line side of meters or metering transformers (CT’s).
Where safety services are installed the SPD to be labelled with additional labelling:
CAUTION
SAFETY (EMERGENCY) SYSTEMS ON SITE
MAY BE DISABLED BY OPERATING THIS DEVICE
Q: Can you use service fuses as SPD for direct metering installations with maximum not exceeding
100A?
Yes. HRC fuses capable of carrying a continuous current of 100A (fuse holder and cartridge;22mm
barrel) to be used as SPD.
Q: What can you use as SPD for direct metering installation with maximum demand exceeding
100A and CT metered installations?
A circuit breaker or combined fuse switch (CFS) unit acceptable by the distributor can be used as
SPD.
This device shall:
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have a continuous current rating to accommodate the maximum demand;
unless otherwise approved by the network operator, have a rated short circuit breaking
capacity of 25kA minimum;
be capable of discrimination with both upstream and downstream protective devices; and
be able to be locked and tagged in the “off” position.
Should be a current limiting device (cannot use a ACB as SPD)
SPD must grade with the Network Operator’s upstream protective device
Q: What are the additional measures to be taken for switchboards rated above 800A?
As per the requirements of AS/NZS 3000 Section 2.5.5 the customer’s switchboard protection
equipment must be able to detect and clear arcing fault currents for switchboards with a load
capacity of 800 A or more.
Switchboards with a capacity of 800 A or more are typically supplied from either a 630 or 1000 kVA
network transformer. The minimum fault levels that should be used to ensure appropriate operation
of protection equipment is 25% of 25 kA for 3 phase faults within 30 km’s of a zone substation.
Q: How to achieve authorised access only for metering equipment?
Meter enclosures and access areas to be locked, provided that a standard approved master key
locking system is fitted to the door of the meter enclosure, cupboard or switchroom.
The following range of locks may be used for enclosures:
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Yale locks
 Type 490 – 25 Camlock (25 mm body length)
 Type 490 – 30 Camlock (30 mm body length)
Lockwood locks
 Type 691 Cupboard Lock
 Type 201 Cylinder (to suit night latch)
 Type 570/2 Cylinder (to suit appropriate lock)
 Type 847/4 Locking “T” handle
Q: Is it mandatory to have the meter panels hinged?
No. Meter panels can be fixed or hinged. The conductors connected to the equipment in the panel
shall be:
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Of sufficient free length to allow the panel to be moved into an inspection or workable
position
Suitably fixed or otherwise retained in position to avoid undue movement or stress on
electrical equipment at equipment terminals
Arranged to prevent undue pressure on electrical equipment mounted behind the panel
Appropriately secured and protected when installed on hinged panels
Wiring not intended to be connected to metering equipment shall not enter the area directly
behind the meter panel(s) unless contained within a physically separate wiring duct or
conduit located in a rear corner of the enclosure or surround such that it does not obstruct
the meter wiring space
In all cases unsealed panel holes must satisfy a minimum protection rating of IP2X
Q: Why do we need to use magnetic screening around meters?
To avoid adverse effect on meters from magnetic fields, adequate spacing is required between the
meters and large current carrying conductors as per below table:
Where spacing cannot be achieved magnetic screening must be installed around the meter.
Screening shall be of a ferrous material, not less than 0.76 mm thick. The meter box must be totally
enclosed around the meter, e.g. enclosed top, bottom, sides and back.
Q: What are the design and construction criteria for outdoor meter boxes?
The enclosure must be constructed of material of sufficient strength to achieve protection against
vandalism, weather and other external factors.
The meter box shall be constructed from:
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Sheet steel with a minimum thickness of 1.0 mm, galvanised
Sheet aluminium with a minimum thickness of 2.0 mm
minimum degree of protection to a rating of IP 24
Where required ventilation and draining shall be provided to:
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Minimise fluctuations in temperature and humidity
Provide an exit point for moisture that may collect within a box
Restrict the entry of insects and vermin
Q: What are the minimum clearance requirements for meter enclosures?
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The internal width and height (excluding panel supports) shall be no smaller than the
required panel size
Clearance from the front of the meter panel to the inside of the door in the closed position
shall be a minimum of 175 mm
Clearance from the back of the meter panel to the rear of the surround, box or assembly
shall be a minimum of 75 mm minimum.
The rear clearance from the back of the meter panel to the rear of the enclosure shall be at
least 150 mm for conductors greater than 16 mm2 up to 35 mm2 (Horizon Power only)
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All enclosures shall be fitted with a hinged door, catch and retainer. A minimum of two (2)
hinges shall be fitted, consisting of a robust lift type, constructed from a non-corroding
material
Meter enclosure need to be earthed
Q: What it the minimum distance from ground to the meter panel that needs to be followed?
This distance depends on couple of things:
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1200 mm for a single direct connected meter
600 mm for multiple and remote reading meter(s)
900 mm in all other cases.
Extract from Western Australian Distribution Connections Manual 2015
Q: What are the acceptable panel sizes for direct wired meters for electrical loads less than or
equal to 100A?
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450 mm high by 225 mm wide with a minimum thickness of 6 mm; or
450 mm high by 450 mm wide with a minimum thickness of 6 mm.
Extract from Western Australian Distribution Connections Manual 2015
Above table illustrates the maximum number of single phase or three phase meters that can be
fitted in these meter panels.
Q: Can you use flexible conductors for panel wiring?
No. Cables shall be stranded copper conductors (building wire) and be:
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Not less than 16 mm2 (7/1.70) for meters with a maximum current limited by an SPD or
Meter Protection Device with a rating of up to 80 A or
Not less than 25 mm2 (19/1.35) for meters with a maximum current limited by an SPD or
Meter Protection Device with a rating of up to 100A.
For multiple master metering arrangements and distributed master metering house services
meters, a neutral reference meter cable system shall be installed. The neutral reference
cable shall be not less than 2.5 mm2 (7/0.67) stranded cable.
Extract from Western Australian Distribution Connections Manual 2015
Q: Where do we use multiple master metering?
Where there is a requirement to measure and record multiple loads such as residential units on a
single lot. Meters are usually grouped and can be either multiple direct connected loads or CT
metered systems.
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The site main switchboard and multiple master metering enclosures shall be installed in the
common area, not be more than 30 metres from the point of supply
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The site main switchboard and each individual metering point must be accessible to
Network Operator personnel without the necessity to traverse property occupied by others.
Extract from Western Australian Distribution Connections Manual 2015
Extract from Western Australian Distribution Connections Manual 2015
Q: Where do we use distributed master metering?
Applies to direct connected master meters and CT connected meters, distributed throughout an
installation. The meters shall not be grouped.
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A distributed master metered installation shall have only one point of supply. The supply to
every installation shall be controlled by a main switch or switches at the site main
switchboard, which shall be located not more than 30 metres from the point of supply
The site main switchboard and each individual metering point must be accessible to
Network Operator personnel without the necessity to traverse property occupied by others
Grouping of individual distributed master meters and their enclosures in either a single or
multiple locations is not permitted unless approved by the Network Operator
If a common service is required (e.g. water reticulation pumps, lighting circuits) it must
originate from and be metered at the site main switchboard
Extract from Western Australian Distribution Connections Manual 2015
Extract from Western Australian Distribution Connections Manual 2015
Q: Where do we use current transformer (CT) connected metering?
Commonly used in most commercial and industrial installations. Used whenever the installation is
connected at low voltage for loads exceeding 100 A and up to 3750 A per phase
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In the design of the customer’s installation, it is necessary to ensure that switchboards,
switch-rooms, metering arrangements and electrical layouts meet the customer’s present
and foreseeable future requirements
Current Transformers (CT’s) and Meter Panels (MP’s) are to be an integral part of the
customer’s electrical switchboard and shall be purchased and installed by the customer’s
electrical contractor
The metering installation will be on two panels consisting of a:
 Foot panel, 600 mm wide by 200 mm high, containing the terminations for the
current transformers and the potential wires;
 Meter panel, 600 mm wide by 400 mm high to mount one meter.
The design shall be such that the SPD grades and discriminates against the Network
Operator’s protection equipment. The main switch protection may be set to values simular
to SPD if discrimination with Sub Boards cannot be obtained.
Three types of current transformer, ‘S’, ‘T’ and ‘W are used as per below table:
Extract from Western Australian Distribution Connections Manual 2015
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The size and maximum number of busbars that will fit through the ‘S’, ‘T’ and ‘W’ type
transformers as follows
Extract from Western Australian Distribution Connections Manual 2015
Extract from Western Australian Distribution Connections Manual 2015
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Refer Appendix K of WA distribution connection manual 2015 for CT wiring schematics, wire
numbers, minimum space requirements for CT and busbar links
Q: Where do we use multiple master CT metering?
This type of arrangement is used where there are more than one CT metered tenancies. May also
include direct metering for house services etc.
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The main switch or switches must be capable of being locked and sealed in the open (off)
position by the Network Operator.
A separate meter panel is required for each current transformer operated meter. This may
also necessitate separate applications for magnetic screening between the kWh meter and
active conductors with current carrying capacity of 150A or greater.
Extract from Western Australian Distribution Connections Manual 2015
Extract from Western Australian Distribution Connections Manual 2015
Reference:
WA electrical requirements
http://www.commerce.wa.gov.au/sites/default/files/atoms/files/waer_2014_0.pdf
Western Australian Distribution and Connection Manual 2015
http://www.westernpower.com.au/documents/WA_Distribution_Connections_Manual.pdf
Prepared By:
Shanaka Unantenne Bsc. Eng (Hons), MIEAust, MIET, MIEEE
Engineering Division- Dara Switchboards